Subtract both sides of the equation by 6.3x to get #x-4<6#. Now, add both sides by 4 to get #x<10#.
For inequalities like this, you can solve it in almost exactly the same way as you do with equalities. You can add or subtract both sides by the same value.
You can multiply or divide both sides by the same value, provided that that value is positive.
If the value you are preparing to multiply or divide to both sides is negative, you flip the sign (#<# to #>#, #># to #<#, #≤# to #≥#, and #≥# to #≤#). For example, given this inequality #-x≤10#, if you multiply (or divide) both sides by #-1#, you have to flip the sign. So it becomes #x≥-10#.
Sometimes when you multiply or divide both sides by the same value, you don't know if it is positive or not (it could be a variable #x#). You can then divide it into two cases. For the first case, assume that it is either positive or zero. Then try to solve it. For the second case, assume that it is negative and don't forget to flip the sign. Then try to solve it. Combine the two solutions to get your answer (if you get #x>2# as your first solution and #-3≤x<-1/2# as your second solution, your final solution would be #-3≤x<-1/2 uu x>2#).
For example, say that you are given the inequality #1/x≥2#. You want to multiply both sides by #x#, but you don't know if it is positive or not. So, you first assume that it is positive or zero. Multiply both sides by #x# then gives #1≥2x#. After dividing both sides by two, you get #x≤1/2#. However, we assumed that #x# was positive or zero, so it must be the case that #0≤x≤1/2#.
Then, we assume that #x# is negative. We multiply the original equation by #x# and flip the sign to get #1≤2x#. Dividing both sides by two, you get #x≥1/2#. But we said that #x# was negative. Thus, the only possible answer is #x≥1/2#.
For harder inequalities, you would need other techniques. You can look those up on the Internet.
